package tui

import (
	"context"
	"fmt"
	"strings"
	"sync"

	tea "github.com/charmbracelet/bubbletea"
	"github.com/charmbracelet/lipgloss"

	"git.tukangketik.id/swanadiva/hostkeeper/internal/models"
	"git.tukangketik.id/swanadiva/hostkeeper/pkg/storage"
)

type keyListState int

const (
	keyListLoading keyListState = iota
	keyListReady
	keyListError
)

// KeyListTab displays and manages SSH key pairs
type KeyListTab struct {
	dataDir string
	keys    []*models.KeyPair
	selected int
	state    keyListState
	err      error
	width    int
	height   int
	mu       sync.Mutex
}

func NewKeyListTab(dataDir string) *KeyListTab {
	return &KeyListTab{
		dataDir: dataDir,
		state:   keyListLoading,
	}
}

func (t *KeyListTab) Name() string { return "SSH Keys" }

func (t *KeyListTab) Init() tea.Cmd {
	return func() tea.Msg {
		store, err := storage.NewJSONStorage(t.dataDir)
		if err != nil {
			return keyListLoadedMsg{err: err}
		}
		keys, err := store.ListKeyPairs(context.Background())
		if err != nil {
			return keyListLoadedMsg{err: err}
		}
		return keyListLoadedMsg{keys: keys}
	}
}

func (t *KeyListTab) Update(msg tea.Msg) (Tab, tea.Cmd) {
	switch msg := msg.(type) {
	case tea.WindowSizeMsg:
		t.mu.Lock()
		t.width = msg.Width
		t.height = msg.Height
		t.mu.Unlock()

	case keyListLoadedMsg:
		t.mu.Lock()
		if msg.err != nil {
			t.state = keyListError
			t.err = msg.err
		} else {
			t.state = keyListReady
			t.keys = msg.keys
		}
		t.mu.Unlock()

	case saveKeyResultMsg:
		return t, t.Init()

	case deleteKeyResultMsg:
		if msg.err != nil {
			t.mu.Lock()
			t.err = msg.err
			t.mu.Unlock()
		}
		return t, t.Init()

	case tea.KeyMsg:
		switch msg.String() {
		case "up", "k":
			t.mu.Lock()
			if t.selected > 0 {
				t.selected--
			}
			t.mu.Unlock()

		case "down", "j":
			t.mu.Lock()
			if t.selected < len(t.keys)-1 {
				t.selected++
			}
			t.mu.Unlock()

		case "ctrl+n":
			return t, func() tea.Msg { return openKeyFormMsg{} }

		case "ctrl+e":
			t.mu.Lock()
			keys := t.keys
			idx := t.selected
			t.mu.Unlock()
			if len(keys) > 0 && idx >= 0 && idx < len(keys) {
				return t, func() tea.Msg { return openKeyFormMsg{editing: keys[idx]} }
			}

		case "delete", "d":
			t.mu.Lock()
			keys := t.keys
			idx := t.selected
			t.mu.Unlock()
			if len(keys) > 0 && idx >= 0 && idx < len(keys) {
				return t, deleteKeyCmd(keys[idx].ID, t.dataDir)
			}

		case "esc":
			return t, func() tea.Msg { return closeFormMsg{} }
		}
	}

	return t, nil
}

func (t *KeyListTab) View() string {
	t.mu.Lock()
	defer t.mu.Unlock()

	if t.state == keyListLoading {
		return lipgloss.PlaceHorizontal(t.width, lipgloss.Center,
			SubtitleStyle.Render("Loading keys..."))
	}
	if t.state == keyListError {
		var b strings.Builder
		b.WriteString(lipgloss.PlaceHorizontal(t.width, lipgloss.Center,
			ErrorStyle.Render(fmt.Sprintf("Error: %v", t.err))))
		b.WriteString("\n")
		b.WriteString(lipgloss.PlaceHorizontal(t.width, lipgloss.Center,
			SubtitleStyle.Render("Press Esc to go back")))
		return b.String()
	}

	type styledRow struct {
		text  string
		plain string
	}
	var rows []styledRow

	title := "SSH Key Pairs"
	titlePlain := title

	if t.err != nil {
		errLine := fmt.Sprintf("Error: %v", t.err)
		rows = append(rows, styledRow{text: ErrorStyle.Render(errLine), plain: errLine})
	}

	if len(t.keys) == 0 {
		empty := "No SSH keys stored."
		hint := "Press Ctrl+N to add a new key."
		rows = append(rows, styledRow{text: SubtitleStyle.Render(empty), plain: empty})
		rows = append(rows, styledRow{text: SubtitleStyle.Render(hint), plain: hint})
	} else {
		for i, key := range t.keys {
			var plain string
			if key.Type != "" {
				plain = fmt.Sprintf("  %s  (%s)", key.Name, key.Type)
			} else {
				plain = fmt.Sprintf("  %s", key.Name)
			}
			var styled string
			if i == t.selected {
				styled = lipgloss.NewStyle().
					Foreground(gbFg).
					Background(gbBgSel).
					Bold(true).
					Render("▸ " + strings.TrimLeft(plain, " "))
			} else {
				styled = lipgloss.NewStyle().Foreground(gbFg).Render(plain)
			}
			rows = append(rows, styledRow{text: styled, plain: plain})
		}
	}

	footerPlain := "Ctrl+Tab:switch  Ctrl+Q:close  ↑↓:nav  Enter:SSH  Ctrl+N:add  Ctrl+F:SFTP  Ctrl+K:keys  Ctrl+P:snippets  q:quit"
	footer := styledRow{text: SubtitleStyle.Render(footerPlain), plain: footerPlain}

	widestRow := lipgloss.Width(titlePlain)
	for _, r := range rows {
		if w := lipgloss.Width(r.plain); w > widestRow {
			widestRow = w
		}
	}
	if w := lipgloss.Width(footer.plain); w > widestRow {
		widestRow = w
	}

	const sidePad = 6
	targetW := widestRow + sidePad*2
	rowShift := (targetW - widestRow) / 2

	var inner strings.Builder

	titleStyled := lipgloss.NewStyle().Bold(true).Foreground(gbYellow).Render(titlePlain)
	inner.WriteString(lipgloss.PlaceHorizontal(targetW, lipgloss.Center, titleStyled))
	inner.WriteString("\n\n")

	shift := strings.Repeat(" ", rowShift)
	for _, r := range rows {
		line := lipgloss.PlaceHorizontal(targetW, lipgloss.Left, shift+r.text)
		inner.WriteString(line)
		inner.WriteString("\n")
	}
	inner.WriteString("\n")
	inner.WriteString(lipgloss.PlaceHorizontal(targetW, lipgloss.Center, footer.text))

	box := BorderStyle.Render(inner.String())
	var b strings.Builder
	b.WriteString(lipgloss.PlaceHorizontal(t.width, lipgloss.Center, box))
	return b.String()
}

func (t *KeyListTab) Close() {}

// keyListLoadedMsg carries the loaded key list
type keyListLoadedMsg struct {
	keys []*models.KeyPair
	err  error
}